Does Photoshop now have a maximum square pixel area that can be "saved for web"?

Does Photoshop now have a maximum square pixel area that can be "saved for web"? I have made some additions to a sprite I am updating for a project. The new sprite dimensions are 298px x 8470px. Previously, the file dimensions were 298px x 8020. When I try to Save For Web the new sprite image gets scaled down to approximately 96% of the intended size. Doesn't matter if I'm saving a PNG or JPG or GIF. When the Save For Web window is open, I try to change it back to 100% in the "Image Size" settings and it won't allow me, saying the values can not exceed a certain amount. I opened the PSD in Fireworks and was able to save for web there with no scaling issues but the file size was crazy high.

I was able to save a PNG that width & height on CS4 on a different machine, just not the most current CS. Thanks.